Circuit controller



Feb. 18, 1936. J. F. TRITLE' CIRCUIT CONTROLLER Filed Oct. 51, 1934Inventor-z John FTr'itle, b

His Attorney.

Patented Feb, 18, 1936 CIRCUIT CONTROLLER John F. Tritle, Erie, Pa.,assignor to General Electrio Company, a. corporation of New YorkApplication October 31, 1934, Serial No. 750,834

11 Claims.

My invention relates to circuit controllers of the type arranged tocarry large values of cur-- rent, and has for an object the provision ofa simple and inexpensive controller which operates efficiently to makeand break the electrical circuit and which insures a minimum resistanceto current flow.

My invention is particularly applicable to controllers used inconnection with direct current railway motors. Heretofore, in the designof controllers much has been desired in minimizing arcing at thecontacts and in providing low resistance current-carrying contacts whichare unaffected by electric arcs. For example, with low resistancecontacts, any arcing between them eventually roughens their surfaces tocause a greatly increased contact resistance. Furthermore in case of anoverload, the contacts may weld to gether to prevent proper operation ofthe controller.

In carrying out my invention in one form thereof, I provide a circuitcontroller with three pairs of contacts, one pair being formed of highconductivity material, the second pair being formed of a good contactmaking material, and the third pair being formed of an arc-resistantmaterial. A. switch member resiliently mounted on anactuating arm isarranged so that the circult is first completed between the second pairof contacts. The resulting current flow energizes a magnet coil which inmagnetically attracting the switch member causes it to rotate about thesec- 0nd pair of contacts and operate with a snap action the first pairof low'resistance contacts into engagement. To open the circuit themagnet coil in biasing the switch member to the closed circuit positioncooperates with the actuating arm which arm first opens the first pairof contacts and then closes the third pair of arcing contacts, the thirdpair of contacts short circuiting a portion of the coil. The resultingreduction in the magnetic force causes the resilient means to 0pcratethe switch member to break the circuit, the arcing contacts being thelast to open. Since only a portion of the coil is short circuited theremainder of the coil is eifective to produce a magnetic flux across thearcing contacts to cause the. quick extinguishment of the are formedbetween them.

For a more complete understanding of my inventicn, reference should nowbe had to the acccmpanying drawing wherein I have shown in Fig. 1' anexploded perspective view of a controller embodying my'invention; Fig. 2illustrates the manner in which the magnet coil is mounted between theblowout plates; Figs. 3 to 6, inclusive,' illustrate diagrammaticallyvarious positions of the controller of Fig. i as it isoperated betweenopen and closed circuit positions while Fig. 7 is a sectional elevationof a portion of the con troller.

Referring to the drawing, I have shown my invention in one form asapplied to a controller til operable by a handle ii to complete aplurality ofcircuits in a predetermined sequence. It is to be understoodthat any number of circuits can be controlled by adding additionalcontrol units to the controller. For the purpose of simplifying thedescription only two control units, 52 and it, have been shown. Thecontrol unit l2 consists of a coil it provided with a plurality of turnsand mounted on a magnetisable core 65 between a pair of magnetizableblowout plates it and ill. As shown in Figs. 7. and 2, the plates itand. ill have portions Mia and ila formed at right angles to the sidesof the blowout plates, the inwardly extending ends of the'portions I601and Ila being spaced apart from each other. A stationary contact 26formed of silver or other suitable high conductivitymaterial is securedto the portions Ilia; and i'lal', while'a second stationary contact 2|formed of a good contact making material such as copper. or tungsten, issecured to the portions We and He in spaced relation with the contact M.A third stationary contact 22 formed of arc-resisting material, such assilver-molybdenum or carbon, is mounted bea tween the ends ltib and libof the plates but electrically insulated therefrom. As shown, thecontact" 22 is in spaced relation with the ends 5% and I'll).

cooperating movable contacts M, 25 and 28 formed respectively of silver,tungsten and silvermolybdenum are mounted on a switch member 2% carriedby an actuating arm 29. A spring 30 encircling a pin 39 which is securedto the switch member 26 biases the switch member 28 into engagement withan extension 32 formed integrally with the actuating arm 29. A. pin 34(Fig. 3) secured to the arm 29 in spaced relatlon with the extension 32extends into a slot 35 provided in the switch member 28. The actuatingarm 29 is mounted on an operating shaft 36 but is free torotatein'dependently of the shaft. By means of a spring3'l encirclingthe shaft, one end 38 of the spring engaging the actuating arm 29 andthe other end 38 engaginga member 40 rigidly securedto the shaft, aforce can be applied by the rotation of the shaft in a counter-clockwisedirection, as viewed in'Fig. 1,

to the actuating arm 26 in afdirection to rotate it towards the closedcircuit position. The extension 26a provided on'the actuating .a'rm26,-a lever 42 pivoted at 46 and a cam 44 rigidly secured to the shaft26, cooperate tooperate the switch member 26 to the open circuitposition in a manner which will later be described more in detail.

. In order to operate the switch member 26 to the closed circuitposition the operating handle H is rotated in a counter-clockwisedirection, as viewed in Fig. l, against the bias of a spring 46 whichnormally urges a roller 46 mounted on a lever 41 pivoted at 46 against anotched positioning cam 45 secured to the shaft 26. The roller 46 andthe notched'cam 46 serve to predetermine different circuit controllingpositions for the handle Thus as the'handle moves in thecounter-clockwise direction a substantial force must be applied to causethe roller 46 to ride over the crest 49a of the cam. As soon as itpasses this crest, however, the spring 45 in biasing the roller againstthe cam assists in moving the shaft 26 until the roller 46 nests withinthe depression 46b. The effect of the spring 45 is to insure a rapidmovement of the handle causing a quick or snap action engagement of thecontacts 2| and 26. v I

During the initial counter-clockwise rotation of the shaft 26 the member46 operating on the end 26 of the spring 21 increases the force in thecoil spring, this force being immediately applied by the opposite end 26of the spring to the actuating member 26 to cause rotation, of theactuating member 26 in a counter-clockwise direction. As shownin Figs. 3and 4 the position of the switch member 26 on the extension-22 is suchthat the movable contact 25 engages its cooperatingstationary contact 2|before either of the. other pairs 26, 24 or 22, 26 engage.

' Consequent to the closing of the contacts 2i and 25 a circuit iscompleted for the flow of current from a supply line indicated at 50, by

.the magnet-coil l4, conductor 5|, portions I61:

and l'la, contacts 2|. and 25 and by a flexible conductor 52 to theother supply line indicated at 52. The coil l4 immediately produces astrong magnetic attractive force on the switch member 26 to operate itwith a snap action in a clockwise direction about the contacts 2| and 25as a fulcrum, causing the silver contacts 26 and 24 to be operated intoengagement one with the other. The final position of the switch member26 is shown in Figs. 5 and 7, the pin 24 occupying a position in theupper end of the slot 25. The

spring 21 and the magnetic attractive force between the magnetizablemembers l6q, Ila, and 26 insures high contact pressure between therelated pairs of contacts 2|, 25 and 26, 24. The circuit making functionperformed by the contacts 2| and 25 prevents arcing as the silvercontacts 26 and 24 close. As will be understood by those skilled in theart, the absence of arcing at the silver contacts eliminates pitting ofthe contacts and insures throughout the life of the controller a currentpath through these contacts of high electrical conductivity.

If it is now desired :to operate the switch member 26 to the opencircuit'position, the operthe spring 26 so that a gradually increasingforce is applied throughthe pin 2| to the switch mem- .ber'26 in adirection to move it to the open circuit pin 24 at a point to the rightof the contacts 2|- and 25. Consequently, this opening force rotates theswitch member 26 about the contacts 2| and 25. Good electrical contactis maintained between these contacts2l and 25, however.- As

- shown, the contact 2| is rounded somewhat to insure a maximum contactarea during the rotation of the member 26. Due to the rotation of themember 26 the silver contacts 26, 26 are first separated, the arcingcontact 26 then moving into engagement with its associated arcingcontact 22 asshown in Fig. 6.

While the switch member 26 is in its fully closed position, Figs. 5 and'1, only a small air gap exists between the switch member and themagnetic frame formed by the blowout plates l6 and I1 so that the majorportion of the magnetic flux traverses the switch member. As the switchmember 26 rotates about the contacts 2| and 26, the air gap between theswitch member a 26 and the ends I60 and Ila of the frame increases. Agreater proportion of the magnetic flux is thereby. shifted between theends I61; and

Ilb' of theframeor blowout plates l6 and I1" preparatory to the openingof the circuit at the contacts 22 and 26.

Continuing with the operation of my invention, the closing of the arcingcontacts 22, .26 short circuits all but the three outer turns of thecoil l4, thereby causing a sudden diminution in the magnetic attractiveforce. The spring 26 thereupon operates the switch member 26 to theopenbetween the pole pieces I61) and I'll) is suflicient to cause arapid extinguishment of the arc.

In case it is desired to control a plurality of circuits inpredetermined sequence additional the unit l2 identical with the unitI2, is provided with a coil 66, magnetizable plates 6| and 62,stationary contacts 62, 64 and 65, movable contacts 61, 66 and 66mounted on a movable switch member 16 secured to an actuating arm 12loosely mounted on the shaft 26. A member 12 secured to the shaftapplies a closing force to the actuating arm 12 through the coil spring'14 and also operates against an extension 12a of the arm 12 to operatethe switch member III to the open circuit position. As shown, the member12 and the actuating arm 12 are angularly spaced in a clockwisedirection from the member 46 and its associated actuating arm 26 so thatthe operating handle ll must rotate through a greater distance beforethe'initial closure of the contacts 64 and 66. Consequently, the devicel2 completes its circuit making function before the device I2 isoperated. The closure of the device l2 occurs as the roller 46 movesinto the depression 16 provided on the notched .control units areprovided. Thus for example,

positioning cam 49, the additional travel of the shaft 36 beingpermitted by the spring 31.

' When the controller I0 is used to connecta plurality of motors firstin series for starting and then in parallel for full speed operation, itis necessary to close a plurality of contacts in sequence to efiect theacceleration of the motors and the partial transition of the seriesconnected motors. The final step in the transition from series toparallel is accomplished by the open-' ing of a contact. This desiredsequence of operation well understood by those skilled in the art, isobtained in accordance with my invention by means of the cam 44 securedtothe shaft 35, this cam beingangularly positioned with respect to themember 42 so that the cam will engage the member 42 after the last unit,for example the unit I3, has been operated to the closed circuitposition. This operation will be clear by first assuming that theoperating handle H has been rotated to close the devices l2 and i3.Further rotation of the handle ll rotates the cam 44 into engagementwith themember 42 causing this member to rotate about its pivot in aclockwise direction to rotate the actuating arm 29 towards the circuitopening position. The operation is then identical with the circuitopening operation by the clockwise rot-ation of the handle ii, the arm29 serving grad= ually to increase the energy stored in the spring 30.As before the switch member 28 rotates in acounter-clockwise directionfirst opening the silver contacts 29, 24 and. then closing the arcingcontacts 22, 26 to short circuit the major portion of the coil i i andcausing the switch -member 28 to be operated to the-open circuitposition with a snap action.

It will be understood that any number of contacts may be operated to theclosed circuit posi= tion in a predetermined sequence and that during Wany point in the operation any one of the contacts may be opened withoutreversing the direction of movement of the operating handle by asuitable arrangement of the actuating arms with respect to the operatingmembers for the desired operation.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto sincemany modifications may be made, and I, therefore, contemplate bythe-appended claims to cover any such modifications as fall within thetru spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent in the UnitedStates is:

1. A circuit controller comprising a switch member operable between openand closed circuit positions, a coil having a plurality of turnsoperatively associated with said switch member, means responsive tomovement of said switch member towards said closed position forenergizing said coil whereupon the magnetic force produced by said coiloperates said switch member to said closed circuit position with a snapaction, resilient means connected to said switch member arranged to bestressed upon an initial movement of said switch member toward said opencircuit position for biasing said switch member toward said open circuitposition, and means responsive to said initial movement of said switchmember for reducing. said magnetic force whereupon said resilient meansoperates said switch member to said open circuit position with a snapaction.

2. A circuit controller comprising a switch member, an operating memberfor operating said switch member between open and closed circuitpositions, pivot means mounting said switch member on said operatingmember to provide for rotation of said switch member, independently ofsaid operating member, a coil having a plurality of turns operativelyassociated with said switch member, means responsive to n Jvement ofsaid switch member towards said closed position for energizing said coilwhereupon the magnetic attractive force produced by said coil operatessaid switch member to said closed circuit position with a snap action,resilient means arranged to beher for suddenly reducing said magneticforce so that said resilient means operates said switch member to saidopen circuit position with a snap action.

3. A circuit controller comprising a switch member, an actuating arm,resilientmeans connecting said switch member to said actuating arm forlimited rotation of said switch member wherer by said switch member isactuated between open and closed circuit positions by movement of saidactuating arm, a coil .mounted adjacent said resilient means andprovided with a plurality of turns for producing a magnetic attractiveforce on said switch member, means operable by movement of said switchmember towards said closed circuit position to energize said coilwhereupon the-attractive force produced by said coil causes said switchmemberto rotate to said closed circuit position, means for rotating saidactuating arm against the bias of said resilient means, the interactionbetween said resilient means and said magnetic attractive force causingsaid switch member to rotate a predetermined distance, and meansresponsive to said rotation for quickly di minishing said magneticattractive force and rendering effective thereby said resilient meansfor operation of said switch member with a snap action to said opencircuit position.

4. A circuit controller comprisingan actuating arm operable between ownand closed circuit positions, a switch member, resilient means securingsaid switch member to said actuating arm and providing for apredetermined rotation of said switch member on said actuating arm, acoil operatively associated with said switch member for producing astrong magnetic attractive force on said switch member, magnetizableplates associated with said coil and forming a flux path between saidcoil and said switch member, a first pair of contacts operable by apredetermined movement of said switch member toward said closed positionto energize said coil whereupon the resulting magnetic attractive forceof said coil rotates said switch member with a snap action about saidfirst'pair of contacts, a second pair of contacts formed of highconductivity material connected in parallel circuit relation with saidfirst pair of contacts and operable by said rotative movement of saidswitch member about said first pair of contacts to a closed circuitposition, a third pair of contacts operatively associated with saidswitch member and arranged when closed to diminish substantially saidmagnetic attractive force, said actuating means when moved toward saidopen circuit position rotating said switch member against the bias ofsaid resilent means to open said second pair of contacts and to.closesaid third pair or contacts whereupon said resilient meansoperates said first pair of "contacts and then operates said third pairof contacts to-isaid open circuit position with a snap action.

5'. A circuit controller comprising an actuating armfoperable betweenopen and closed circuit positions, a switch member, resilientrneanssecuring said switch member to said actuating arm' and providing for apredetermined rotation of said switch member on said actuating arm, a

coil operatively associated with said switch member and provided with aplurality of turns, magnetizable plates associated with said coil andforming a flux path adjacent to said switch member, a first pair ofcontacts. operable by predetermined movement of said member toward saidclosed position to energize said coil whereupon the resulting magneticattractive force of said coil rotates said switch member with a snapaction about said first pair. of contacts, a second pair of contactsformed of high conductivity material connected in parallel circuitrelation with said first pair of contacts and operable by said rotativemovement of said switch member to a .closed circuit position, a thirdpair oficontacts connected in parallel circuit relation with said firstand second pairs of contacts arranged when closed to short circuit asubstantial number of the. turns of said coil, said actuating arm whenoperated toward said open, circuit position operating said switch memberagainst the bias of said resilient means to open said first pair ofcontacts and to close said third pair of contacts whereupon theshortcircuiting of said coil diminishes said magnetic force to causesaid resilient means to open said second pair of contacts and then toopen said third pair oi contacts with a snapv action, said magneticplates being provided with 1 extensions arranged on opposite sidesofsaid,

third pair of contacts so that the flux produced therebetween by saidcoil quickly extinguishes arcs formed between said third pair ofcontacts.

6. A circuit controller comprising an actuating arm operable betweenopen and closed circuit positions, a switch member, resilient meanssecuring said switch member to said actuating arm, a lost motionconnection between said switch member and said actuating arm spaced fromsaid resilient means and providing for a predetermined rotation of saidswitch member on said actuating arm, a coil operatively associated withsaid switch member and provided with a plurality of turns for producinga strong magnetic attractive force on said switch member, a first pairof contacts operable by a predetermined movement of said switch membertowards said closed position to energize said coil whereupon theresulting magnetic. attractive force of said coil rotates said switchmember with a snap action about said first pair of contacts, a secondpair of contacts formed of high conductivity material connected inparallel circuit relation with said first pair of con tacts and operableby said rotative movement of said switch member about said first pair ofcontacts to a closed circuit position forming a low resistance currentpath, a third pair of contacts arranged when closed to short circuit asubstantial number of the turns of said coil, said resilient means, saidlost motion connection and said coil being so arranged that uponmovement of said arm towards said open circuit position said second pairof contacts is first opened, and said third pairof contacts is closed,and then said third pair of contacts is opened by said resilient meanswith a snap action.

7. A circuit controller comprising a switch member, actuating meanspivotally supporting said switch member intermediate its ends for op-'eration between open and closed circuit positions,

resilient means biasing said switch memberagainst said actuating means,a first pair of contacts one of which is operable by said switch memberinto engagement ,with the other; a coil provided with a-plurality ofturns connected in series circuit relation with said first pair ofcontacts, a magnetic frame energized by said coil to produce on saidswitch member a magnetic force causing a pivotal movement of said switchmember on said actuating means against the bias of said resilient means,a'second pair of contacts one of which is operable into engagement withthe. other contact with a snap action by said pivotal movement of saidswitch'member, a third pair of contacts one of which is operable by saidswitch member into and out of engagement with the other contact, said"actuating means when moved plying a-force to said'actuating arm whensaid shaft is rotated in a circuit closing direction, a member forpositively engaging said arm when said. shaft is rotated in a circuitopening direction, a switch member, resilient means securing said switchmember to said arm at one point thereof, a lost motion connectionbetween said switch member and said arm and in spaced relation with saidresilient means, a first pair of contacts one of which is operable bysaid switch member into engagement with the other, a coil.

provided with a plurality of turns connected in series circuit relationwith said first pair of con-' tacts, a magnetic frame energized by saidcoil to produce on said switch member a magnetic force.

to rotate said switch member in a predetermined direction about saidfirst pair of contacts, a second pair of contacts one of which isoperable into engagement with the other contact by said rotation of saidswitch member, a third pair of contacts one of which is operable by saidswitch member into and out of engagement with the other contact, saidshaftwhen rotated in said circuit opening direction operating throughsaid resilient connection to rotate said switch member in a'reversedirection to open said first pair of contacts and to close said thirdpair of contacts, connections completed by the closing of said thirdpair of contacts for diminishing the magnetic attractive force of. saidcoil and said frame whereupon said resilient means operates said switchmember to said open circuit position with a snap action.

9. A circuit controller comprising an operating ,shait rotatable inopposite directions between open and closed circult positions, anactuating direction, a member forv rigidly engaging said arm when saidshaft is rotated in a circuit opening direction, a switch member,resilient means securing said switch member to said arm at one I pointthereof, a lost motion connection between said switch member and saidarm in spaced relation with said resilient means, a' first pair ofcontacts one of which is operable by said switch member into engagementwith the other, 'a coil providedwith a plurality of turns connected inseries circuit relation with said first pair of contacts, a magneticframe energized by said coil to produce on said switch member a magneticforce causing said switch member to rotate in a predetermined directionabout said first pair of contacts, a second pair of contacts one ofwhich is operable into'engagement with the other contact by saidrotation of said switch member, a third pair of contacts one of which isoperable by said switch member into and out of engagementwith theothercontact, said shaft when rotated in said circuit opening directionoperating through said resilient means and said lost motion connectionto rotate said switch member in a reverse direction to open said firstpair of contactsand to close said third pair of contacts, connectionscompleted by the closing of said third pair of contacts for diminishingthe magnetic attractive force on said switch member, said resilientconnection thereupon operating said switch member to said open circuitposition with a snap action, said frame being provided withextensions'located on opposite sides of said third. pair of, contactsfor producing therebetween a strong magnetic flux.

10. A circuit controller comprising a plurality of switch membersoperable between open and closed circuit positions, a coil operativelyass'o: elated with each switch member, means responsive toapredetermined movement ofsaid switch members towards said closedcircuit positions for energizing respectively said coils, the magneticattractive force produced by each coil operating its-oorrespondingswitch member to its closed circuit position with a .snap action,resilient ,means'connected to each switch member, an operating'handleoperable between open and closed c ircuit, positions, connecting meansincluding said resilient means between said handle and said switchmembers for operating said switch members in'predetermined sequence fromsaid open to said closed circuit positions, and means operableby saidhandle in said circuit closing direction to operate one of said switchmembers to said open circuit position, said operating member producingthrough said resilient means a force on said switch member in thecircuit opening direction and means responsive to an initial movement ofsaid switch member for reducing said magnetic force whereuponsaidresilient means operates said switch member to said open circuitposition with a snap action.

11. A circuit controller comprising an actuating arm operable betweenopen and closed circuit positions, a switch member, resilient meanssecuring saidswitch member to said actuating arm in a predeterminedposition and providing for a predetermined rotation of said switchmember on said actuating arm, a first pair of con tacts operable intoclosed circuit position by predetermined movement of said actuating armtowards its closed circuit position, a second pair of contacts, meansresponsive tothe closing of said first pair of contacts for rotatingsaid switch member on said actuating arm to operate quickly said secondpair of contacts to a closed circuit position, a third pair of contactsoperable by movement of said actuating arm against the bias ofsaid'resilient means towards said open circuit position to a closedcircuit position after the opening of said second pair of contacts, and

means responsive to the closing of said third pair of contacts forcausing said resilient means .to operate said switch member to said opencircuit position.

JOHN F. TRITLE.

